The present invention concerns a method for determining control data for triggering a restraining device or devices in a vehicle, according to which information is transmitted between two neighboring vehicles which is used in activating the restraining device or devices in the event of a crash.
Many different restraining devices designed to protect vehicle occupantsxe2x80x94e.g. front airbags, side airbags for the head and chest regions, knee airbags, seat-belt pretensioners, etc.xe2x80x94will be installed in vehicles in the future. The purpose of these restraining devices is to offer vehicle occupants optimum protection against injury in as many different accident situations as possible. It would be contrary to this purpose to trigger the restraining devices independently of various parameters such as, for example, the severity of the accident, the direction of impact, the sitting position of the vehicle occupants and the like. To do so would even raise the risk that the restraining devices themselves might injure the occupants in being triggered. There is, therefore, an expressed need for the xe2x80x9cintelligentxe2x80x9d triggering of restraining devices based on the aforesaid parameters, as suggested by the conference report of the Third International Symposium on Sophisticated Car Occupant Safety Systems, Airbag 2000, Karlsruhe, Nov. 26-27, 1996, pp. 16-1 to 16-20.
Vehicles are already commonly equipped with seat occupancy sensors, which detect whether a vehicle seat is in fact occupied and whether, given the instantaneous sitting position of the vehicle occupant, the triggering of restraining devices will protect the occupant or will instead cause injuries. Sensors for detecting seat occupancy are described, for example, on pp. 17-1 to 17-12 of the above-cited conference report cited above.
It is also apparent from the same document that the appropriate triggering of restraining devices, especially of side airbags, is possible only if an impending crash is detected in advance. So-called pre-crash sensors, preferably based on the radar principle, are used for this purpose. With the aid of such pre-crash sensors, it is possible to detect at an early stage the direction from which the impending crash is likely to come and the nature of the obstacle causing the crash, for example a moving vehicle or a rigid object.
A method set forth by way of introduction, according to which information concerning the distance between neighboring vehicles is transmitted between them, is described in German Published Patent Application 44 42 189. This distance information is used in the activation or preparation of restraining devices for protecting the vehicle occupants in the event of a crash between the two vehicles.
The information concerning the distance between the two vehicles does not in itself bring about a notable improvement in the adjustment of the triggering behavior of the restraining devices to the course of a crash that may ensue. An object of the invention is, therefore, to indicate a method which makes it possible to adjust the triggering behavior of the restraining device or devices to the course of the crash in the greatest possible degree, thereby affording the vehicle occupants optimum protection.
The aforesaid objective is achieved in that each of two neighboring vehicles transmits to the other information concerning its own vehicle-specific characteristics that can affect the course of an impending crash.
It is particularly advantageous to modulate these vehicle-specific data upon the transmitted signals of pre-crash sensors of the vehicles. The vehicles then do not need any communication arrangement of their own for these vehicle-specific data. The transmitted signals of the pre-crash sensors can be modulated with the vehicle-specific data with respect to frequency or amplitude or phase or pulse width. The transmission medium for the pre-crash sensors can be microwaves or light waves or ultrasonic waves.
It is advantageous that the vehicle-specific data modulated on a transmitted signal are not demodulated by a receiver until the pre-crash sensor receiving the transmitted signal has measured a distance to the other vehicle that is below a presettable threshold.
Characteristics that can be transmitted as vehicle-specific signals are, for example, the weight of the vehicle and/or its front body structure and/or its body rigidity and/or the model of vehicle and/or the vehicle speed. When a vehicle receives these vehicle-specific data transmitted by the other vehicle involved in the crash, it can derive from them appropriate control data for its restraining device or devices, so that only such restraining device or devices will be activated, in such a chronological sequence and with such force, as will optimally protect the occupants of the vehicle during the crash.